High speed diesel oil engine



Dec. 13, 1932. F; POR CH 1,891,010

HIGH SPEED DIESEL OIL ENGINE Filed Jan. 4. 1929 Patented Dec. 13, 1932 UNITED STATES PATENT OFFICE FERDINAND PORSCHE, OF STUTTGART-UNTERTURKHEIM, GERMANY, ASSIGNOR T0 DAIMLER-BENZ AKTIENGESELLSCHAFT, OF STUTTGABT-UNTERTUIRKHEIM, GER- MANY, A COMPANY OF GERMANY HIGH SPEED DIESEL OIL ENGINE Application filed January 4, 1929, Serial No. 330,337, and in Germany October 15, 1928.

The present invention relates to Diesel oil engines and has for its chief object to provide an improved pre-ignition chamber particularly for high speed Diesel oil engines.

The introduction of the Diesel system in high speed engines, for example for vehicle and aircraft engines, renders it necessary to overcome a number of difliculties in these en: gines. The latter consist particularly in the fact that correspondingl to the small cylinder units small quantities of fuel, fluctuating with the load, have to be injected, thoroughly atomized and distributed in the charge air, in order to achieve a smokeless combustion from running without load up to maximum speed.

These difliculties are obviated and improved results are obtained according to the invention by constructing the pro-ignition chamber in such a manner that certain ratios of space, cross-section and dimensions and certain shapes of same are followed.

In order to more clearly explain the invention reference may now be had to the accompanying drawing in which Figures 1 and 2 show diagrammatically a pre-ignition chamber according to the invention and Figure 3 shows a constructional form. of a pre-ignition chamber according to the invention.

The fuel is injected in a conical jet through the nozzle a into the pre-ignition chamber.

In compartment I of this chamber there is mounted for example an incandescent burner b which serves to ignite the mixture when the engine is started. This burner is cut-out during running. The compartment I is, in the known manner, ofcylindrical shape, the diameter being considerably greater than the height. Its lower end opening to the adj oining compartments may be funnel-shaped. The adjoining compartment II is of considerably smaller diameter than the compart-,

ment I. To this compartment for example a number of circular channels are connected, which together form a compartment III. These channels terminate in an annular compartment IV of low height, which communicates with a hollow conical compartment V- and passes into the circular channel VI, which connects the chamber with the combustion chamber 0 of the working cylinder. In this connection the volumes of the compartments II, III, IV, V and VI together are for example in the proportion of 3:11 to the volume of compartment I. If the volume of compartment VI is taken as a unit, the volumes of the part compartments are in the following proportions Compartment V is 45 times the volume of compartment VI, compartment IV is 67 times the volume of compartment VI, compartment III is 10-11 times the volume of compartment VI, compartment II is 100-105 times the volume of compartment VI, compartment I is 430-450 times the volume of compartment VI. The added volumes of the compression space and the pre-ignition chamber are 3 to 4% times the total cubical content of said compartments I-VI.

From this it will be seen that commencing with compartment VI each subsequent part compartment is greater in volume than the preceding part compartment. For perfect combustion at all speeds and load stages the ratios of the cross sectional areas of the compartments are quite as important as the compartment volume ratios. The ratios of the cross sectional areas of the compartments do not vary, however, similarly to the ratios of the volumes of the compartments, but small cross-sectional areas alternate with larger cross-sectional areas. If the cross-sectional area of the compartment VI is again taken as unlt, the cross-sectional area of the com partment IV is 4-5 times the cross sectional area of compartment VI. The cross-sectional area of compartment III onthe contrary, which is formed by the distributor channels is, however, only 2-2.5 times the cross sectional area of compartment VI, whilst the cross-sectional area of compartment II is 7-8 times the cross-sectional area of compartment VI.

In addition, in order to obtain a good atomization and combustion at all speeds of the engine, the distance of the injector nozzle from the surface d of the so-called burner, with respect to the diameter atthis point of the burner, is of importance. By being considerably under or in excess of a certain ratio,

the quantity of fuel particles sprayed from the 'jet and burnt for the pre-ignition chamber ignition, would be unsuitably varied, and thus lead to defective combustion and the deposit of soot. The most suitable proportion. has been found to be the ratio of 1 to 2.5 or 3 between the diameter of the surface at and the distance of this surface from the nozzle.

Slight deviations from the given ratios are permissible, without substantial variations occurring in the working of the engine.

A further feature of the invention consists in the construction of the so-called burner e of the pro-ignition chamber, Fig. 2. The sleeve 7 and the bottom It containing the atomization channels g, as also the adjoining pivot-like member '5, form one piece. The cover is serving to close the chamber is connected with the sleeve 7 and is screwed into the cylinder Z in common therewith.

What I claim is In a high speed Diesel oil engine, a working cylinder and a pre-ignition chamber therefor, said pre-ignition chamber comprising a first compartment, fuel injection means associated with said compartment, said compartment being of cylindrical form and being greater in diameter than in height, a second compartment of less diameter than and communicating with the first compartment, a third compartment constituted by a plurality of channels having an aggregate cross sectional area less than the second mentioned compartment and communicating therewith, a fourth compartment of annular form communicating with and of greater cross sectional area than the third compartment but of less cubical content than the latter, a fifth compartment communicating with Q the fourth compartment and constituted by a hollow annular cone-shaped passage, a sixth compartment constituted by an outlet passage in communication with the fifth compartment through which gas is admitted to the engine 45 cylinder, each of said compartments being of less cubical content than the preceding compartment, the volume of said chamber being to the volume of the compression chamber of the engine cylinder plus the volume of said chamber as one is to from three and one-half to four and one-half.

In testimony whereof I afiix-my signature.

FERDINAND PORSCHE. 

